Science：椿象用变色保护后代
发布人：管理员 浏览次数： 发布时间：2016-01-09
底部糊着报纸的一只装着椿象(Podisus maculiventris，如图所示，它的下面是幼卵)的笼子似乎不太可能推动科学发现，但正是那报纸上的填字游戏的黑白方格引导昆虫学家、正在加拿大蒙特利尔大学攻读博士学位的Paul Abram开始怀疑，椿象在产卵时采取的策略可能超乎想象。许多动物，如鸟类和其它昆虫，会根据饮食的不同和其它因素而产下不同颜色的卵，但科学家们从来没有观察到有动物母亲故意改变所产的卵的颜色。Abram注意到，椿象在黑色方格上产的卵颜色更暗，反之亦然。虽然伪装可能是对这一现象的解释，但后续实验——只让椿象在白色织物上产卵——揭示出这些颜色存在其它功能。根据今天发表于《当代生物学》的研究，雌性椿象可以根据表面反射掉的光线程度来选择性地添加黑色素，从而改变卵的颜色。由于色素具有吸收紫外线光的能力，研究人员相信它的功能是保护正在发育的幼虫的脆弱的DNA和细胞机制。Abram把它比喻成防晒霜。在野外，椿象在树叶上产卵。更多的实验表明，它们在顶部(阳光直射下)产下颜色更深的卵，而在树叶背面的阴暗处所产的卵所含的色素比平均水平要少2.1倍。这种色素是什么仍然是一个未知数，但早期的实验表明，它可能同地球上最浓重的深色色素——黑色素相关。
原文链接：
Stink bugs protect their eggs by changing their color
原文摘要：
Newspaper lining the bottom of a stink bug (Podisus maculiventris, pictured, with eggs at bottom) cage may seem an unlikely impetus for scientific discovery, but it was the black and white squares of the crossword puzzle that that led Paul Abram, an entomologist working towards his Ph.D. at Université de Montréal in Canada, to suspect that stink bugs might be employing a surprising strategy when laying their eggs. Plenty of animals, like birds and other insects, lay eggs that differ in color based on what their parents eat or other factors, but scientists have never observed mothers intentionally changing the color of their eggs. Abram noticed that the eggs on the dark squares tended to be darker and vice versa. Although camouflage might be a tempting explanation for the phenomenon, subsequent experiments, in which the stink bugs were given only white fabric to lay their eggs on, revealed that the pigments served a different function. According to research published today in Current Biology, female stink bugs can change the color of their eggs depending how much light is reflecting off a surface by selectively adding a dark pigment. Because of the pigment’s ability to absorb UV light, the researchers believe that its function is to protect the delicate DNA and cellular machinery inside the developing bug. Abram likens it to sunscreen. In the wild stink bugs lay their eggs on leaves, and additional experiments showed that the bugs placed darker eggs on the top (in direct sunlight), wheras eggs on the shaded underside of the leaf contained 2.1 times less pigment on average. The identity of the pigment is still unknown, but early experiments suggest that it may be related to melanin—the most abundant dark pigment on the planet.
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